After a long day of hiking, swimming and other physical pursuits, card games are a nice way to wind things down. A single deck of cards offers a multitude of games, including Go Fish, Crazy Eights and Old Maid. (Check out 10 Family-friendly Card Games for more great ideas.) Cards are also an excellent distraction in the event of rainy weather. So, slip a deck or two into your backpack -- you never know when they might come in handy.